Method and means for indicating the position of a drilling bit in a well casing



c. BURTY- V `July 9; T1935.-

METHOD AND MEANS FOR `INDICATING THE POSITION oF AV DRILLING` BIT 1N A'WELL cAsING Filed Sept. 12, '1934 "INI/ENTOR. v @f/wm BY" ATTORNE.

t Patented Julya 193e tirarsi) STA-'r Eis PATENT OFI-ICEl 2,007,465 e tMETHOD AND MEANSFOR INDICATING THE POSITION OF A nmLLrNG Brr 1N A WELL IClarence E. Burt, Los Angeles, Calif., assignor to A Baker Oil'l'ooyls,`Inc., Huntington Park, Calif., I

` a' corporation of California 1 Amiiicatnmseptember 12, 19341,` serialNo. 743,644 sclaims. (c1. 25e- 1) This invention relates to the art ofdrilling deep oil wells and particularly pertains to a method and meansfor indicating to the driller at the surface thefdepth ofthe bit in thetbore.

" 5 `In practicallyall oilelds it is common practice to discontinuedrilling just before entering the oil sands and to set a stringofcasing. This casing `is 'cemented into placel-and acts 'to prevent thewalls from caving and to exclude waters and gases from intermediatestrata vfrom migrating along the casing. After this casing is set andcemented in,` drilling is` usually proceeded with vinto lower strata orinto the oil producing sands.

For various reasons it is desirable that the driller be able todetermine whenn the drilling bit is passing through the lowerendofthis'casing;` and therefore it isthe principalv objectof the pres--lentinvention to provide a method andgmeans form s indicating tothe.driller that the' drill isgorjhas penetrated through the ylower Jendofthel casing.

To practice my invention, I iit the lower end of the casing with amember formed of drillable material and which willrbe eng'aged bythedrill when I it is' desired to` proceedwiththe drilling through thecasing. This member is so constructed that a visible indication willbegiven to thedriller by the circulating `uid when the drill commencespulverizing thesame.

One form which the invention may assume' is exempliiied in thefollowin`g^descriptionand vil-v lustratedby way of examplein theaccompanying` drawing, inwhich: Fig.` 1 is a view in central verticalsection through an oil well bore showing the water string of casing settherein andthe drilling aboutxto be e proceeded with, the lcasingbeingttedfwith a device for practicing my invention.

Fig. 2 is an enlarged `central vertical section through a device forpracticing 4my invention.

`In .practically all instances the water string of casing. III for anoil well bore is fitted at itsv lower end with what is knownas a casingshoe I I which in turn is usuallyfltted` with a'guide plug or a' guidefloat plug I2. The function and operation of these devices is well knownand understood and in prior practice these plugs have been construct-led out of such materials as concrete and cast iron in order that theycan be drilled out.

My present invention contemplates so constructing such a plug that whenit `is drilled up,'a

Vvisible indication will be givenftat the mouth ofthe well indicating tothe driller that the drill is t passing through the lower end of thewater string of casing, To accomplish lthis I prefertto `construct theplug out of a granular or lapideous ma-t terlal such as a-concretemixture so that when it is pulverized by the drill, the granularVparticles thereof will be carried to the surface by the circulatingfluid.v I intend that the drilling of this plug furnish a visibleindication in the drilling fluid that the drill is-penetrating throughthe lowerend of the water string. For this purpose. during theconstructionof the plug, aV quantity ofcoloring agent is added to thecement mixture so that the `material when drilled up will be of a colorclearly distinguishable from the drilling mud or fluid. In actualpractical have found that iron or. ferric oxide FeaOs is a very suitableagent for this purpose and I prefer to use this agent in When such `amixture is used,the`material of the plug assumesv avery vividredcolorclearly distinguishable from the drilling mud,` and when thedrillpulverizles the plug and these cuttings are ,carried to rthesurface by the drilling mud'.

Etheycan be readilyV detected, thereby indicating tothe driller that thedrill is penetrating` through the lower end of the water string ofcasing. y

the present instance, I have` also shown a second medium for indicatingthat the drill is penetrating through the lower end of the' casing.

This second medium is a coloring agent which is ahi'ghly concentratedwater "soluble red dye in dry powder form. The dye which I have used inpractice is what is` known as Safranine dye.

-This'dye iscontainedjin dry form in chambers I4 formed within the plugso' that when the drill pulverizes the plus, this dyewill be releasedinto the mud or circulating fluid, khighly coloring the `same so thatwhen this uid reaches the surface,

a clear visible indication will be given to the driler that the drill ispenetrating through the shoe of the water string. e l

In the present instance, I have enclosed the drypowder dye in two glassvials which are embedded withinvthe plug during the formation thereof;'Theamount of dye which I have used is `approximately one-half ounce,which I have .found will' giveV a very definite distinguishing color(red), to approximately one barrel of cir--l culating fluid.

I havefound that the plug is satisfactory withthatthe dye can be'usedalone without coloring the'material of the plug, but, however, I preferJ to use both. V

t Inthe present instance, I have disclosed -nrv invention'as'beingpracticed by means of the l x l plug forming the guide or oat shoe butit is obvious, v'of course, that this is not essential as it may bepracticed in various other ways.

In practicing the invention, the plug is constructed as previouslydescribed and the water string of casing is set in place and cementedin. This cementing process usually leaves from twenty to forty feet ofcement tailings in the lower end of the well casing which must bedrilled up. After the casing has been cemented in, the drill is rundownwardly through the casing to drill up the cement tailings remaininginthe casing and to proceed through the casing into lower strata. Duringdrilling, of course, mud fluid is circulated downwardly through thedrill pipe, returning up the casing to the surface.

When the drill commences penetrating the plug at the lower end of thecasing, the returns will show the cuttings of the plug due to theirbeing of a color clearly distinguishable from the mud. Likewise, whenthe drill pulverizes the plug releasing the Safranine dye, this dye willimmediately color the mud fluid so that the returns at the mouth willclearly indicate to the Ydriller that the drill is penetrating kthroughthe lower end of the casing. This gives the driller an accurate check onthe depth and also has a number of other advantages. e

While Il have shown the preferred form of my invention, it is to beunderstood that various changes may be made in its construction by thoseskilled in the art withoutjdeparting from the spirit of the invention asdeiined in the appended claims.

Having thus described my in\ ention, what I claim and desire to secureby Letters Patent is:

1. A method of determining when the drilling bit passes a certain pointin a well casing ina deep oil well which includes the step ofpositioning a drilling iluid coloring agent in the well casing at saidcertain point where it will be released into the drilling iiuid.V by thedrilling bit when the latter passes that point. f

2. A method of indicating that the drilling bit passing through a wellcasing in `a deep oil well has passed a certain point in the well casingwhich includes the step of positioning a circulating fluid coloringagent consisting of a highly concentrated dry dye within the casing atsaid point in amanner whereby it will be released into the drillingfluid when the drilling bit passes said point.

a. A method of indicating that the arming bit Vhas penetrated throughthe lower end of a string of well casing in a well bore which includesthe step of positioning a drilling fluid coloring agent in anobstructing position within the `lower end of Asaid casing in a mannerwhereby it will be released into the drilling iiuid to color the same'when the drilling bit passes through the lower end of the casing.

4. A method of indicating that the drilling bit has passed through thelower end of a. string of well casing in a Well bore which comprisessecuring a drillable container in the lower end of the well casing andcontaining a highly concentrated circulating uid coloring agent, saidcontainer being positioned to be drilled up by the drilling bit as itpasses through the lower -end of the well casing to release saidcoloring well casing, container means mounted interiorly of said tubularmember and adapted to obstruct the passage ofa drill through saidtubular member, said container means being capable of being drilled upby a drilling bit, and a highly concentrated coloring agent containedwithin the container means whereby it will be released into the drillingmud when the drilling bit penetrates said container means. l

7. As an article of manufacture, a casing shoe adapted to be secured tothe lower end of va well casing, a plug secured within said casing shoe.and of a material capable of being drilled up,

said plugcontaining a highly concentrated circulating iluid coloringagent which will be re' leased into the circulating uid while a drillingbit is drilling'up" said plug.

8. As an article ofmanufacture, a casing shoe to be fitted to'the lowerend of a string of well casing, a cementitious plug secured in saidcasing shoe, the cementitious material of which said plug is formedbeing highly colored in contrast with the drilling fluid, said plughaving a chamber formed therein, and a highly concentrated dye in saidchamber releasable into the circulating fluid when the plug is drilledup by a drilling bit.

CLARENCE E. BURT.

